Contamination caused by fingerprints is one of the most frequent contaminations occurring on various display devices, high-glossy electronic devices or building materials. Such contamination is clearly visible and causes an exterior defect on a product. Recently, as the fingerprint contamination on a surface of a display device has increased with the development of touchscreen interface technology of electronic devices, there is an increasing demand for resolving the problem of the fingerprint contamination on the surface of display devices.
However, until now, no technology actually realizing anti-fingerprint coating has been developed, although anti-contamination coating has just been developed in the sense of easy cleaning.
For example, WO09/72738 discloses a anti-fingerprint coating composition for a stainless steel external case of an electronic appliance, which contains 10.6 parts by weight or less of an additive composed of 27.6 to 36.2 parts by weight of polysilicate, 10.6 parts by weight or less of any one selected from epoxy and vinyl resins, 21.2 to 42.6 parts by weight of colloidal silica, at least one selected from the first group consisting of —OH, —NH2, and —COOH, and at least one selected from the second group consisting of —CnF2n+1 and —SiR3.
U.S. Patent No. 2002/0192181 discloses an anti-contamination composition, which includes a cured or crosslinked polymer having no perfluoropolyether moieties, and a fluid fluorinated alkyl- or alkoxy-containing polymer or oligomer.
However, the above-mentioned anti-contamination film uses fluorine-based coating, such that a contaminant transferred to its surface is easily wiped due to low surface energy. Since the anti-contamination film does not have a function of self-cleaning, that is, a function of actively reducing transfer of fingerprints or decomposing fingerprints, the appearance may not be improved without wiping the contaminant off.
A conventional anti-fingerprint film can be applied only to a steel plate used for an external case, and has a limit in application to a product requiring high light transmittance such as a display device.
Meanwhile, a coating solution, a coating layer, and a coating method using the same were also developed in the self-cleaning sense using an enzyme. However, the coating solution, layer and method have been developed to prevent adherence of marine microorganisms to the bottom of a ship, but not to reduce contamination caused by fingerprints on display devices, the appearance of electronic devices, and building materials.
For example, a self-polishing, anti-contamination coating composition is disclosed in U.S. Patent No. 2008-0038241, and a method of preventing contamination of an underwater device by marine microorganisms is disclosed in U.S. Pat. No. 5,998,200.
That is, in the self-cleaning sense using an enzyme, the conventional coating solution, layer or method has a mechanism of previously removing an adsorbent material produced by marine microorganisms to prevent marine microorganisms from adhering to the bottom of a ship or removing a contaminant with the adsorbent material, but this mechanism is not associated with the decomposition of the fingerprint contaminant.
As far as the present inventors know, there is no technology of anti-fingerprint coating in the self-cleaning sense, which can be used to provide an anti-fingerprint property to the surface of a display device.